The present invention relates to a dispenser pump and more particularly to a dispenser pump of novel design excellent in assembling feasibility, durability and in avoidance of deterioration by the trouble from contents.
The conventional containers containing cosmetics, detergents and other liquid- or paste-formed contents are usually provided with dispenser pumps on their openings so as to discharge the contents in desired quantities. Referring to FIG. 1 which shows the structure of such a dispenser pump according to the conventional art, a button 3 formed with a nozzle 4 is seen as provided on the top of a screwed cap 2, which cap is screwed to the top opening part of a container 1. Under the button 3, a stem 6 and a piston 9 connected to the stem are provided so as to be moved vertically by a spring 8 housed in a cylinder housing 10. A sealing member 12 is disposed on the circumference of the piston 9. The cylinder housing 10 is provided, at its inner bottom, with a check valve 14 in the form of a ball and is provided with an opening 15 at its bottom end. The reference number 5 stands for an aluminum cap covering the exterior of the screwed cap 2, the number 16 for an over-cap and the number 18 for a gasket.
Further, another piston 20 usable for so-called airless type dispensers acts to raise the underneath contents as it rises due to the reduced pressure in the air space of the container 1.
Thus, upon pressing the button 3, the stem 6 with the piston 9 is lowered against the elastic force of the spring 8 to cause the contents in the cylinder housing 10 to be flowed up along the channel formed inside the stem 6 before being ejected through the nozzle 4, with the check valve 14 simultaneously blocking the lower end of the cylinder housing 10. On the contrary, when the button 3 is released, the check valve 14 is opened due to the reduced pressure on the side of the cylinder housing 10 as the stem 6 together with the piston 9 are moved up by the elastic force of the spring 8, so that the contents in the container 1 may be flowed in the cylinder housing 10.
Incidentally, in this type of conventional dispenser pumps as shown in FIG. 1, fluid contents such as cosmetics come in contact with the spring 8 made of a metal like steel, because the spring 8 is located inside the cylinder housing 10 under such an overall arrangement. Thus, there is caused a problem in that the spring 8 gets rusted, deteriorating the quality of the contents coming in contact with the spring 8.
To overcome this problem, a dispenser pump was proposed to avoid the contents from directly contacting the metal spring 8, by locating the spring 8, instead of the inside of the cylinder housing 10, between the internal bottom surface of the button 3 and the top surface of a screw cap 2, as shown in FIG. 2. With this dispenser pump, however, in the assembling step, the number of assemblies to be assembled is relatively large, because three sets of assembling units, i.e. the assembly including a stem 6 and a piston 9, the assembly including a cylinder housing 10 and a check valve 14 and the spring 8 are required. This results in the complicated assembling process and wider assembling space. Even in the case of assembling with an automatic equipment, there is still the problem of complication in the respect of material feeding devices and assembling devices, also because of the many parts to be assembled. In addition, a further problem may be caused, because the button 3 tends to disengage easily from the stem 6 due to the pressing force of the spring 8, as the button 3 driving-fitted on the stem 6 gets loose with time, as the spring 8 is elastically pressed directly against the bottom surface of the button 3.
The present invention, which is devised in the consideration of the problems with conventional dispenser pumps as described above, is designed to provide a dispenser pump of novel construction, wherein the metallic spring of the dispenser pump does not come in direct contact with the contents to protect the spring against corrosion and the contents against deteriorative change, and on the other hand, both the assembling process and the construction of an automatic assembling device can be simplified due to the reduced auxiliary assemblies in the assembling step. Further, the present invention is also intended to provide a dispenser pump of novel construction excellent in durability by securing against the disengagement of the button from the stem by the elastic force of the spring.
Therefore, according to an aspect of the present invention, there is provided a dispenser pump comprising a screwed cap 2 connected to the opening part of a container 1, a button 3 provided vertically movably on the top of the screwed cap 3 and formed with a nozzle 4, a stem 6 connected to a lower part of the button 3 so as to communicate with the nozzle 4, a cylinder housing 10 provided with a check valve 14 in an opening part 15 at the lower end of the housing, a top part of the cylinder housing 10 being connected to the screwed cap 2, a piston 9 connected to the lower part of the stem 6 to be vertically movable in the cylinder housing 10 and a sealing member 12 provided on the circumference of the piston 9, wherein the dispenser pump includes further an upper ring member 22 fitted on the upper part of the stem 6, the position of the upper ring member being restricted by a stopper 21, and a lower ring member 24 fitted on the lower part of the stem 6 and positioned at an upper part of the piston 9, so that a spring 8 can be elastically provided between the upper ring member 22 and the lower ring member 24.